Add accidentally dropped disable_irb command back

lib/irb/default_commands.rb

@@ -2,32 +2,33 @@
 
 require_relative "command"
 require_relative "command/internal_helpers"
-require_relative "command/context"
-require_relative "command/exit"
-require_relative "command/force_exit"
-require_relative "command/chws"
-require_relative "command/pushws"
-require_relative "command/subirb"
-require_relative "command/load"
-require_relative "command/debug"
-require_relative "command/edit"
+require_relative "command/backtrace"
 require_relative "command/break"
 require_relative "command/catch"
-require_relative "command/next"
-require_relative "command/delete"
-require_relative "command/step"
+require_relative "command/chws"
+require_relative "command/context"
 require_relative "command/continue"
+require_relative "command/debug"
+require_relative "command/delete"
+require_relative "command/disable_irb"
+require_relative "command/edit"
+require_relative "command/exit"
 require_relative "command/finish"
-require_relative "command/backtrace"
-require_relative "command/info"
+require_relative "command/force_exit"
 require_relative "command/help"
-require_relative "command/show_doc"
+require_relative "command/history"
+require_relative "command/info"
 require_relative "command/irb_info"
+require_relative "command/load"
 require_relative "command/ls"
 require_relative "command/measure"
+require_relative "command/next"
+require_relative "command/pushws"
+require_relative "command/show_doc"
 require_relative "command/show_source"
+require_relative "command/step"
+require_relative "command/subirb"
 require_relative "command/whereami"
-require_relative "command/history"
 
 module IRB
   module Command
@@ -235,6 +236,10 @@ def load_command(command)
       [:history, NO_OVERRIDE],
       [:hist, NO_OVERRIDE]
     )
+
+    _register_with_aliases(:irb_disable_irb, Command::DisableIrb,
+      [:disable_irb, NO_OVERRIDE]
+    )
   end
 
   ExtendCommand = Command

test/irb/command/test_disable_irb.rb

@@ -0,0 +1,28 @@
+# frozen_string_literal: false
+require 'irb'
+
+require_relative "../helper"
+
+module TestIRB
+  class DisableIRBTest < IntegrationTestCase
+    def test_disable_irb_disable_further_irb_breakpoints
+      write_ruby <<~'ruby'
+        puts "First line"
+        puts "Second line"
+        binding.irb
+        puts "Third line"
+        binding.irb
+        puts "Fourth line"
+      ruby
+
+      output = run_ruby_file do
+        type "disable_irb"
+      end
+
+      assert_match(/First line\r\n/, output)
+      assert_match(/Second line\r\n/, output)
+      assert_match(/Third line\r\n/, output)
+      assert_match(/Fourth line\r\n/, output)
+    end
+  end
+end